On pilot studies for robotic therapy: the relevance of healthy subjects’ motor control responses to protocol design

The maintenance of balance in dynamic conditions (e.g. during walking) is a necessary requirement that motor control must reach to avoid falls. However, this is a challenging situation, since to ensure the forward progression of the body, the center of mass must stay outside the base of support in the sagittal plane, and simultaneously remain inside the lateral borders in the frontal plane. Deviation from normative data of healthy subjects in dynamic balance could be used to quantify gait stability, fall risk and to provide hints for rehabilitation. However, normative data can be influenced by age, sex, anthropometry and spatio-temporal gait parameters, and such differences among subjects and leg side can hamper accurate assessment. The aims of this study were to investigate, in a group of healthy subjects: (1) possible asymmetry in dynamic balance maintenance strategies between leg sides, (2) the influence of age, sex and anthropometry on stability and (3) its dependence by spatio-temporal gait parameters. A total of 34 healthy subjects aged between 21 and 71 years, and ranging from 50.1 to 101.6 kg of body mass and from 155.0 to 188.9 cm of height were assessed on spatio-temporal and dynamic balance parameters (Foot Placement Estimator at heel strike and Margin of Stability at mid-stance) during self-selected gait. No parameter showed differences between legs. Dynamic balance parameters were influenced by sex, age, body mass and height mainly in the frontal plane. These measures were also correlated with gait speed and stride length both in the antero-posterior and medio-lateral directions. In addition also cadence and step width influenced the stability in the sagittal and frontal planes, respectively. The findings of this study confirm the symmetry in motor control of dynamic balance during self-selected gait in healthy subjects. Sex, anthropometry and spatio-temporal gait parameters have a significant effect on stability parameters, and this should be taken into account in dynamic balance studies.

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Temporal Dynamics of Corticomuscular Coherence Reflects Alteration of the Central Mechanisms of Neural Motor Control in Post-Stroke Patients

Frontiers in Human Neuroscience ◽

10.3389/fnhum.2021.682080 ◽

2021 ◽

Vol 15 ◽

Author(s):

Maxime Fauvet ◽

David Gasq ◽

Alexandre Chalard ◽

Joseph Tisseyre ◽

David Amarantini

Keyword(s):

Motor Control ◽

Healthy Subjects ◽

Voluntary Movement ◽

Temporal Dynamics ◽

Elbow Extension ◽

Stroke Patients ◽

Post Stroke ◽

Antagonist Muscles ◽

Agonist And Antagonist ◽

Agonist And Antagonist Muscles

The neural control of muscular activity during a voluntary movement implies a continuous updating of a mix of afferent and efferent information. Corticomuscular coherence (CMC) is a powerful tool to explore the interactions between the motor cortex and the muscles involved in movement realization. The comparison of the temporal dynamics of CMC between healthy subjects and post-stroke patients could provide new insights into the question of how agonist and antagonist muscles are controlled related to motor performance during active voluntary movements. We recorded scalp electroencephalography activity, electromyography signals from agonist and antagonist muscles, and upper limb kinematics in eight healthy subjects and seventeen chronic post-stroke patients during twenty repeated voluntary elbow extensions and explored whether the modulation of the temporal dynamics of CMC could contribute to motor function impairment. Concomitantly with the alteration of elbow extension kinematics in post-stroke patients, dynamic CMC analysis showed a continuous CMC in both agonist and antagonist muscles during movement and highlighted that instantaneous CMC in antagonist muscles was higher for post-stroke patients compared to controls during the acceleration phase of elbow extension movement. In relation to motor control theories, our findings suggest that CMC could be involved in the online control of voluntary movement through the continuous integration of sensorimotor information. Moreover, specific alterations of CMC in antagonist muscles could reflect central command alterations of the selectivity in post-stroke patients.

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The Motor Control Output Forming in Healthy Subjects and Parkinson’s Disease Patients

Basal Ganglia and Thalamus in Health and Movement Disorders ◽

10.1007/978-1-4615-1235-6_26 ◽

2001 ◽

pp. 293-305 ◽

Cited By ~ 2

Author(s):

Sergey P. Romanov ◽

Michael G. Pchelin

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Motor Control ◽

Healthy Subjects ◽

Control Output

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Brain Activity during Lower-Limb Movement with Manual Facilitation: An fMRI Study

Neurology Research International ◽

10.1155/2015/701452 ◽

2015 ◽

Vol 2015 ◽

pp. 1-14 ◽

Cited By ~ 4

Author(s):

Patrícia Maria Duarte de Almeida ◽

Ana Isabel Correia Matos de Ferreira Vieira ◽

Nádia Isabel Silva Canário ◽

Miguel Castelo-Branco ◽

Alexandre Lemos de Castro Caldas

Keyword(s):

Motor Control ◽

Lower Limb ◽

Healthy Subjects ◽

Brain Activity ◽

Verbal Stimulus ◽

Limb Movement ◽

Lower Limbs ◽

Normal Brain ◽

Lower Limb Movement ◽

The Right

Brain activity knowledge of healthy subjects is an important reference in the context of motor control and reeducation. While the normal brain behavior for upper-limb motor control has been widely explored, the same is not true for lower-limb control. Also the effects that different stimuli can evoke on movement and respective brain activity are important in the context of motor potentialization and reeducation. For a better understanding of these processes, a functional magnetic resonance imaging (fMRI) was used to collect data of 10 healthy subjects performing lower-limb multijoint functional movement under three stimuli: verbal stimulus, manual facilitation, and verbal + manual facilitation. Results showed that, with verbal stimulus, both lower limbs elicit bilateral cortical brain activation; with manual facilitation, only the left lower limb (LLL) elicits bilateral activation while the right lower limb (RLL) elicits contralateral activation; verbal + manual facilitation elicits bilateral activation for the LLL and contralateral activation for the RLL. Manual facilitation also elicits subcortical activation in white matter, the thalamus, pons, and cerebellum. Deactivations were also found for lower-limb movement. Manual facilitation is stimulus capable of generating brain activity in healthy subjects. Stimuli need to be specific for bilateral activation and regarding which brain areas we aim to activate.

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Motor Control of Rapid Sequential Finger Tapping in Humans

Journal of Neurophysiology ◽

10.1152/jn.01173.2004 ◽

2005 ◽

Vol 94 (3) ◽

pp. 2162-2170 ◽

Cited By ~ 12

Author(s):

R. Arunachalam ◽

V. S. Weerasinghe ◽

K. R. Mills

Keyword(s):

Motor Control ◽

Healthy Subjects ◽

Magnetic Stimulation ◽

Radial Direction ◽

Motor Evoked Potentials ◽

Finger Tapping ◽

Reverse Direction ◽

Finger Movement ◽

Mechanical Explanation ◽

Timing Difference

We investigated in 29 healthy subjects a simple model of rapid independent finger movement: the rapid sequential tapping of adjacent fingers. Inter-tap interval (ITI) was measured for adjacent pairs of fingers in each direction. ITI was shorter in the ulnar→radial direction than in the reverse direction [ P < 0.001 for middle to index (M→I) compared with index to middle (I→M)]. There was a gradient across the hand such that in the ulnar→radial direction, little to ring (L→R) tapping was fastest and M→I slowest; in the radial→ulnar direction, the reverse was the case. Rectified surface electromyography (EMG) from finger extensors and flexors was averaged with respect to either the first or second tap. The interval between the flexor EMG burst and the tap was similar irrespective of the order of finger tapping, excluding a mechanical explanation of the timing difference. Transcranial magnetic stimulation (TMS) was applied at 0- to 50-ms intervals after the first tap. Interposed TMS delayed the second tap significantly more ( P < 0.001) in the M→I direction than in the I→M direction. Motor-evoked potentials (MEPs) evoked by TMS interposed between taps showed a greater facilitation in the M→I than in the I→M direction ( P < 0.001). Increasing intensity of TMS rendered subjects unable to produce the second tap, more frequently in the I→M direction than in the M→I direction. We have demonstrated a consistent pattern across the hand and postulate that finger-order-dependent differences in ITI and the gradient of these across the hand may reflect the mechanism of grasping and further that the cortical programming of finger tapping differs depending on finger order.

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Robotic therapy for chronic stroke: general recovery of impairment or improved task-specific skill?

Journal of Neurophysiology ◽

10.1152/jn.00336.2015 ◽

2015 ◽

Vol 114 (3) ◽

pp. 1885-1894 ◽

Cited By ~ 33

Author(s):

Tomoko Kitago ◽

Jeff Goldsmith ◽

Michelle Harran ◽

Leslie Kane ◽

Jessica Berard ◽

...

Keyword(s):

Motor Control ◽

Skill Learning ◽

Three Dimensions ◽

Learning Mechanisms ◽

Reaching Task ◽

Movement Trajectories ◽

Robotic Therapy ◽

General Improvement ◽

And Function ◽

Clinical Measures

There is a great need to develop new approaches for rehabilitation of the upper limb after stroke. Robotic therapy is a promising form of neurorehabilitation that can be delivered in higher doses than conventional therapy. Here we sought to determine whether the reported effects of robotic therapy, which have been based on clinical measures of impairment and function, are accompanied by improved motor control. Patients with chronic hemiparesis were trained for 3 wk, 3 days a week, with titrated assistive robotic therapy in two and three dimensions. Motor control improvements (i.e., skill) in both arms were assessed with a separate untrained visually guided reaching task. We devised a novel PCA-based analysis of arm trajectories that is sensitive to changes in the quality of entire movement trajectories without needing to prespecify particular kinematic features. Robotic therapy led to skill improvements in the contralesional arm. These changes were not accompanied by changes in clinical measures of impairment or function. There are two possible interpretations of these results. One is that robotic therapy only leads to small task-specific improvements in motor control via normal skill-learning mechanisms. The other is that kinematic assays are more sensitive than clinical measures to a small general improvement in motor control.

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The Prospective Study of Apparently Healthy Subjects Who Consolted for Their Annual Health Checkup-I: The Protocol Design

Japanese journal of MHTS ◽

10.7143/jhep1985.19.2_24 ◽

1992 ◽

Vol 19 (2) ◽

pp. 24-24

Keyword(s):

Prospective Study ◽

Healthy Subjects ◽

Protocol Design ◽

Health Checkup ◽

Apparently Healthy

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Changes in Muscle Strategies During Landing Task in Subjects With and Without Knee Genu Varum

Journal of Modern Rehabilitation ◽

10.18502/jmr.v14i2.7708 ◽

2021 ◽

Author(s):

Mahboobeh Azizi ◽

Khosrow Khademi ◽

Mehri Ghasemi ◽

Alireza Akbarzadegan

Keyword(s):

Motor Control ◽

Knee Joint ◽

Lower Limb ◽

Healthy Subjects ◽

Muscle Activation ◽

Control Strategies ◽

Trunk Muscles ◽

Genu Varum ◽

Significant Difference ◽

Offset Time

Introduction: Onset and offset activation of lower limb and trunk muscles may change the knee with genu varum during landing. These motor control strategies can be different from those in healthy subjects and contribute to more injuries in lower extremities. This study aimed to compare the delay time of the onset activity of the abdominal and lower limb muscles in the specific landing task. Materials and Methods: Ten females with genu varum deformity and ten females with normal knee participated in this case-control study. Genu varum deformity was measured by a camera capturing goniometer. The subjects were informed to land by preferred lower limb from a table (30 cm high) on a force plate. Vertical Ground Reaction Force (VGRF) was measured to clarify the onset of the landing task. Surface Electromyography (sEMG) of transverse abdominal/int. oblique (TA/IO), Vastus Medialis (VM), Vastus Lateralis (VL), Lateral Gastrocnemius (LG), and medial gastrocnemius (MG) muscles were recorded during landing. The difference between the onset activity of the above muscles and onset of VGRF was calculated as delay times and compared between muscles and between two groups. Also, the offset of activities and the intensity of muscle activation (normalized RMS) were compared between the two groups. Results: Lower limb and trunk muscles showed significantly different onset of activities in the genu varum group (P<0.05), whereas there was no significant difference in the onset of muscle activities in the healthy group. Results indicated significant differences between two groups in TA/IO, LG, and MG muscles and the genu varum group had longer delay time for motor control strategy (especially ankle strategy) in the landing task. Offset time of all muscles in the genu varum and healthy subjects had a significant difference between muscles, especially in gastrocnemius muscles (P<0.05). Also, there were significant changes between the two groups in LG and MG muscles (P<0.05). Normalized muscle activities (nRMS) generally indicated an increase in muscle activation of genu varum subjects (TA/IO, LG, MG) compared with the normal subjects (P<0.05). Conclusion: Motor control strategies in landing task is different in the genu varum group due to changes in biomechanics and properties of the knee joint. This variation may be due to changes in proprioception afferent pathways around the knee joint. An increase in muscle activation, delay, and offset time of muscle activities in these subjects, indicated that an increase in the degree of freedom may change motor control strategies. Internal anticipation and postural adjustment of the landing task in these subjects need more motor unit recruitment (an increase in nRMS). This deformity in the knee joint might affect some activities and possibly cause knee changes such as osteoarthritis.

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